.NET programming interface for R&S GTSL and R&S EGTSL

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1 Application Note SE001_0e.NET programming interface for R&S GTSL and R&S EGTSL Application Note Products: ı R&S CompactTSVP ı R&S PowerTSVP ı R&S GTSL ı R&S EGTSL This application note describes the use of R&S GTSL and R&S EGTSL in a.net programming environment. It shows the user how libraries and drivers generated using the C programming language can be used in applications based on.net technology. Note: Please find the most up-to-date document on our homepage This document is complemented by software. The software may be updated even if the version of the document remains unchanged

2 Table of Contents Table of Contents 1 Introductory Note Introduction The GTSL-.Net Wrapper Classes Technology Adding.NET Wrapper Classes Tips for Creating GTSL-.NET Wrapper Classes GTSL Device Driver Example: The Pfg Class GTSL Library Example: The ResMgr Class GTSL Programming Examples Direct Driver Calls Combi Test Installation Procedure Development Tools Compiler csc.exe from the.net Framework SDK Visual Studio Community Resources SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 2

3 Introductory Note 1 Introductory Note This application note uses the following abbreviations for Rohde & Schwarz instruments and software products: Unless a distinction must be made between the two, both the R&S CompactTSVP TS- PCA3 production test platform and the R&S PowerTSVP TS-PWA3 production test platform are referred to as the TSVP (test system versatile platform). Unless a distinction must be made between the two, both R&S GTSL (generic test software library) and R&S EGTSL (enhanced generic test software library) are referred to as GTSL. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 3

4 Introduction 2 Introduction The TSVP production test platform is a standardized, modular platform for programcontrolled testing of modules and instruments during production or in the lab. GTSL is a collection of software libraries and the supporting software device drivers. These libraries control the TSVP hardware modules for performing test tasks such as measurements, wiring configurations or signal generation. GTSL was generated using the C/C++ programming language. To permit GTSL to be used from programming languages such as C#, Visual Basic.NET and other languages based on the.net framework, Rohde & Schwarz provides a software layer to link the two programming worlds. This software layer is presented in this application note. It is referred to here as the GTSL-.NET wrapper classes. This application note explains how the existing GTSL software libraries and software instrument drivers are encapsulated so that they can be accessed from the.net world. Finally, it explains how programming examples that are part of the GTSL installation can be used in a slightly modified form in the.net world under C#. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 4

The GTSL-.Net Wrapper Classes 3 The GTSL-.Net Wrapper Classes 3.1 Technology In order to create a link layer between code written in C and code run in a.

5 The GTSL-.Net Wrapper Classes 3 The GTSL-.Net Wrapper Classes 3.1 Technology In order to create a link layer between code written in C and code run in a.net environment, the 'unmanaged C code' must be embedded in the 'managed code' of a.net-based programming language such as C#. Running 'managed code' requires the use of a runtime library such as that made available by the.net framework, whereas the compiled 'unmanaged C code' is built into the machine language. Special care must be taken to replace the parameter interface for the embedded C functions with equivalent, i.e. compatible data types in the.net world. The GTSL-.NET wrapper classes for GTSL libraries and GTSL device drivers are provided to the user as the GTSL.dll class library in.net format, compatible with.net framework 3.5. The.dll extension is the only reminder of the old Win32 DLLs in GTSL, although the class library is not compatible with these in any way. The source code for all wrapper classes and the corresponding Microsoft Visual Studio solution are included. For each of a large number of GTSL libraries and GTSL device drivers, the class library for the GTSL-.NET wrapper layer includes a class with public methods representing the functions provided by that library or device driver Adding.NET Wrapper Classes In some situations, the user will have test libraries created in C or GTSL libraries for which no GTSL-.NET wrapper classes exist. This section describes how to create a.net wrapper class to allow the user to make these libraries available in a.net environment. This newly created wrapper class can be included in the published source code in the GTSL.dll. Wrapper classes insert functions from an existing DLL created in the C programming language by means of DllImport: GTSL.dll - source code module: Pfg.cs SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 5

6 The GTSL-.Net Wrapper Classes The PInvoke class lists all functions of a C GTSL device driver (in this example the device driver for the R&S TS-PFG signal generator), which are then published to the.net world using DllImport. The function rspfg_configureoperationmode was used here as being representative for all functions of the driver. Its parameter list includes the three parameter types HandleRef, string and int. The header file of the C device driver contains the rspfg_configureoperationmode function with the following parameter list: rspfg.dll - source code module: rspfg.h The type definitions for the parameter list is taken from the National Instruments VISA software layer (VISA: Virtual Instrument Software Architecture). The VISA type definitions correspond to the ANSI-C data types as well as to the C# data types used in the.net wrapper classes as listed in the following table. Instead of the C# data types, the wrapper classes could just as easily use the equivalent.net data types. NI VISA ANSI-C C#.NET ViSession* unsigned long* out IntPtr (1) out IntPtr (1) ViSession unsigned long HandleRef (2) HandleRef (2) ViConstString const char* string String ViRsrc char* string String ViStatus signed long int Int32 ViStatus* signed long * out int out Int32 ViAttr unsigned long uint UInt32 ViString char* string String ViChar[] char[] StringBuilder StringBuilder ViBoolean unsigned short ushort UInt16 ViBoolean* unsigned short out ushort out UInt16 ViInt16 signed short short Int16 ViInt16* signed short* out short out Int16 ViUInt32 unsigned long uint UInt32 ViUInt32* unsigned long* out uint out UInt32 ViInt32 signed long int Int32 ViInt32* signed long * out int out Int32 ViReal64 double double Double ViReal64* double* out double out Double ViReal64[] double[] double[] Double[] (1) IntPtr is a handle to a resource such as is returned by a GTSL device driver when the C function <driver_name>_initwithoptions( ) is called. (2) HandleRef is an object that contains a handle to a resource (IntPtr). The Invoke mechanism passes it to the unmanaged code, i.e. to the C functions of the GTSL device driver when they are called. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 6

7 The GTSL-.Net Wrapper Classes All C functions of a GTSL device driver added to the private class PInvoke by means of DllImport are again encapsulated in public methods in order to provide error handling and also to simplify the parameter signature somewhat. These methods can then be called by users in their own applications. All GTSL-.NET wrapper classes that control the TSVP hardware modules are derived from the TsvpInstrument base class. This base class defines abstract methods that must be included in all wrapper classes. The wrapper class uses methods of the same name to overwrite these with the override modifier. The TsvpInstrument base class additionally defines data types in the form of enums that are used by all derived wrapper classes. The base class also includes classes for error handling and administration of the attributes for the individual GTSL device drivers and their wrappers. Attributes that are found in all wrappers are included here in the attribute dictionary, which lists the attributes such as name, data type, reuse in various channels, read/write access and a brief description. The attribute dictionary can additionally include special attributes for a specific GTSL-.NET wrapper class Tips for Creating GTSL-.NET Wrapper Classes The.NET programming environment handles several items more elegantly than was the case in the C world. Some brief examples are provided here Length of array parameters The C language GTSL device drivers and libraries contain functions that receive an array of elements in the parameter list. If the length of the array is variable instead of fixed, an additional parameter must be specified here with the length of the array. For example, the rspfg_createarbwaveform function in the C device driver for the R&S TS-PFG signal generator: rspfg.dll - source code module: rspfg.h The wfmsize parameter defines the number of elements in the array wfmdata[]. The length parameter is no longer required in the corresponding method in the GTSL-.NET wrapper. The length of the array is determined via the Length method in the array object and thus transferred in the call of the corresponding PInvoke method: SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 7

The GTSL-.Net Wrapper Classes GTSL.dll - source code module: Pfg.cs 3.1.2.

One example is the C function named <driver_name>_revision_query, which returns version information about the software device driver and about the firmware for the addressed hardware.

If the strings transferred to this function in a C application are too short, it can result in difficult-to-find errors or system crashes.

8 The GTSL-.Net Wrapper Classes GTSL.dll - source code module: Pfg.cs Using the StringBuilder class: size adjustments Several GTSL device driver functions return information to the user in the form of one or more strings. One example is the C function named <driver_name>_revision_query, which returns version information about the software device driver and about the firmware for the addressed hardware. The call to this function must include two strings with a minimum length of 256 characters. If the strings transferred to this function in a C application are too short, it can result in difficult-to-find errors or system crashes. C# provides a convenient security mechanism for preventing this problem. It ensures that in all GTSL-.NET wrapper classes, objects of the StringBuilder class that the user transfers to the corresponding methods either provide sufficient memory or are increased in size as needed. The base class TsvpInstrument provides the EnsureStringBuilderCapacity method for this purpose. It checks the size of the transferred StringBuilder object. If not sufficient, the capacity of the object is increased: GTSL.dll - source code module: TsvpInstrument.cs The wrapper class derived from the base class uses this method to check the StringBuilder objects that the user transfers to a given method. The example below uses the RevisionQuery method: GTSL.dll - source code module: Pfg.cs SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 8

9 The GTSL-.Net Wrapper Classes Enum and classes of parameter values In the C language GTSL device drivers and libraries, the parameter values that can be transferred to functions are usually defined in the associated header file using the compiler statement #define. In a.net programming environment, groups of parameter values are typically combined either in an enum (in the case of integers) or in a class. During the method definition, the name of the enum or the class of parameter values is defined as the parameter type. This is a benefit to the user when using the method in an application because the code editor in Microsoft Visual Studio uses the IntelliSense function to display a list of all possible parameter values for the current position. The user selects the desired value from the list using the arrow keys and then presses the Enter key to accept. This reduces the likelihood of invalid parameter values or mistyped parameter names. The IntelliSense function offered by the Microsoft Visual Studio code editor is described in more detail in the following chapter Converting parameter types: string and integer <> enum The previous section explained why enum parameters are preferred in the GTSL-.NET wrappers, while the C programming world often uses predefined integer parameter values or strings (character arrays) as the input and output parameters. This means that in the wrapper classes, input parameters of the enum type must be converted into strings or integer values, which are then transferred to the C device drivers. This process is performed in reverse for output parameters. For string input parameters, the conversion can be performed easily using the GetName() method of the enum class. The only consideration is to ensure that the names of the enum elements match the required strings. In the case of integer input parameters, the enum element must be forced into an integer data type by prefixing the (int) type conversion operator to perform an explicit type conversion. An additional consideration for output parameters is that parameter values returned by a C function might not have a matching value in the enum. In this case, integer parameters are checked using the enum method IsDefined() to determine whether the returned value is defined in the enum. If so, the parameter value can be converted into the enum type by means of the type conversion. In the case of string parameters returned by a C function, the enum method TryParse() can check whether the string matches an element name for the enum. If so, the method returns the identified enum value. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 9

10 The GTSL-.Net Wrapper Classes 3.2 GTSL Device Driver Example: The Pfg Class In this example, a C application calls the R&S TS-PFG signal generator function rspfg_configurestandardwaveform for the GTSL device driver DLL rspfg.dll as follows: PfgCExample.exe - source code module: PfgCExample.c The same functionality in a C# application is shown on the next page: SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 10

11 The GTSL-.Net Wrapper Classes PfgCSharpExample.exe - source code module: PfgCSharpExample.cs First, the new operator generates an instance of the Pfg class. In this example, signalgenerator was used as the name of the instance. All public methods of that class can then be called, e.g. signalgenerator.configurestandardwaveform( ). The namespace of the GTSL.dll being used, which includes the Pfg class, is named RohdeSchwarz.Gtsl. In the above example, this is included in the using list at the start of the code. To permit the GTSL.dll to be used in the user's application, it must be inserted into the project, for example by using the "Add reference..." command in Microsoft Visual Studio. The parameters are transferred to the methods more conveniently than with the C functions. The signal generator channel being configured is easily selected using the IntelliSense function in the Visual Studio development environment, for example. In the corresponding C function, a string containing the channel name would have to be transferred at this point. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 11

12 The GTSL-.Net Wrapper Classes The class diagram created by Visual Studio for the Pfg class displays all methods, enum types (e.g. the two signal generator channels) and additional subclasses representing parameter constants. All methods of the Pfg class: SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 12

in the Pfg class: Selects one of the two channels of

Signal generator trigger inputs for starting a

Three output modes for the generator: Default

13 The GTSL-.Net Wrapper Classes Examples of enum types defined in the Pfg class: Selects one of the two channels of the PFG signal generator. Possible default waveforms. Signal generator trigger inputs for starting a waveform output. Three output modes for the generator: Default waveforms Arbitrary waveforms Arbitrary waveform sequences SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 13

14 The GTSL-.Net Wrapper Classes 3.3 GTSL Library Example: The ResMgr Class The resource manager is a central component for GTSL libraries. It includes functions for administering the instrument setup in a test system. Like all other GTSL software libraries, the resource manager is written using the C programming language. In a C application, the RESMGR_Setup function is called as follows: GtslLibraryExampleC.exe - source code module: GtslLibraryExampleC.c SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 14

15 The GTSL-.Net Wrapper Classes In a C# application, the same function is called as follows: GtslLibraryExampleCSharp.exe - source code module: GtslLibraryExampleCSharp.cs In this example, it can be seen that the parameter list of the setup method is significantly shorter than the equivalent setup function in C. This is because the return parameters for assessing any errors could be eliminated. The Exception mechanism from C# is used for error handling. Like all other wrapper classes for GTSL libraries, the ResMgr class is derived from the base class GtslCommon. This includes classes for error handling and methods used by all library wrapper classes. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 15

16 The GTSL-.Net Wrapper Classes The class diagram generated by Visual Studio for the ResMgr class shows all methods, defined constants and error codes in the class: SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 16

17 GTSL Programming Examples 4 GTSL Programming Examples 4.1 Direct Driver Calls This example shows how to combine GTSL library calls and GTSL device driver calls within an application. The setup method of the GTSL-.NET wrapper class for a GTSL library opens all of the device drivers required by the library. If a device driver is used by more than one GTSL library, the session handle for the driver is automatically shared by all participating libraries. The GTSL resource manager manages the exchange of the session handle for device drivers. It administers the session handle for each instrument contained in the physical.ini configuration file for the test system. If a device driver must be called directly from the application, for example because the GTSL library does not support a specific method call, the corresponding session handle must be requested of the resource manager. In a mixed application of GTSL libraries and GTSL device drivers, a device driver must not be opened twice, i.e. via the library and in parallel directly via the device driver. Although it is theoretically possible, it conflicts with the 'state caching' mechanism of the internal device state used by the IVI drivers. This data is no longer valid if the device is accessed via two different driver instances. Note that in the following C# source code, the session handle for the PFG signal generator requested of the resource manager is transferred to the overloaded constructor of the Pfg class when the class is instantiated. This serves to inform the instance that it need not (and in fact must not) open the device driver itself. A subsequent call of Pfg.Init( ) would generate an exception with the following error text: "This instance, created by using a resource manager handle, does not allow calling this method!" : "The device is already initialized!". This same applies to the Pfg.Close( ) method, which also must not be called in this situation. The Cleanup method of the GTSL-.NET wrapper class of the last GTSL library which uses the PFG signal generator is responsible for closing the device driver. The session handle becomes invalid after the Cleanup method of the library ends. No more method calls of the instance of class Pfg are possible then. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 17

18 GTSL Programming Examples - continued on next page - SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 18

19 GTSL Programming Examples Source: ProgramDirectDriverCall.cs SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 19

20 GTSL Programming Examples 4.2 Combi Test The Combi Test program shows how to create a combined in-circuit test and functional test application in C# using the following GTSL libraries: - Resource Manager - Signal Routing Library - In-Circuit Test Library - continued on next page - SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 20

21 GTSL Programming Examples Source: ProgramCombiTest.cs SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 21

22 Installation Procedure 5 Installation Procedure The installation program for the source code of the GTSL-.NET wrapper classes can be downloaded from the Rohde & Schwarz homepage: The name of the installation file is InstallerGtslWrapper.msi. Installation is started by right-clicking the file and selecting 'Install' from the context menu. If GTSL is already installed on the target machine the GTSL-.NET wrapper classes will be installed to directory <GTSL directory>\develop\.net wrapper. If GTSL is not installed yet, the installation directory is C:\Program Files (x86)\rohde-schwarz\gtsl\develop\.net wrapper. To build the GTSL.dll simply open the Visual Studio solution GtslWrapper.sln which is located in the installation directory and choose in the Configuration Manager whether to build a debug or release version of the DLL. After the build process the GTSL.dll can be found in the directory \.net wrapper\gtsl\bin\release (or Debug). To use the GTSL-.NET wrapper classes in any project either the GTSL.dll can be added to the project with the menu 'Add reference ' in Visual Studio or all relevant source code files can be added to the project. The necessary source code files are located in the subdirectories Common, Instruments and Libraries below directory \.net wrapper\gtsl\. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 22

Development Tools 6 Development Tools Users who do not install paid copies of Microsoft Visual Studio Professional or Enterprise Edition on their development PC still have options to create, quickly

23 Development Tools 6 Development Tools Users who do not install paid copies of Microsoft Visual Studio Professional or Enterprise Edition on their development PC still have options to create, quickly and at no additional cost, their own C# test applications that include the GTSL-.NET wrapper classes. 6.1 Compiler csc.exe from the.net Framework SDK The.NET framework SDK includes a C# compiler that can be launched from the command line. It is called csc.exe and is located in the following path: C:\Windows\Microsoft.NET\Framework\v3.5\csc.exe. The code to be compiled must be created in a separate text editor. This path should be added to the Windows system path variable Path so that the compiler can be called from any directory on the PC. The Combi Test programming example from section 4.2 is shown here as an example of a call of the csc.exe compiler: This call generates the console application ProgramCombiTest.exe. It is a 32-bit application that references the GTSL.dll class library. 6.2 Visual Studio Community Microsoft offers a free version of its Visual Studio development environment, called Visual Studio Community. This version can be used under the conditions published by Microsoft. The functionality corresponds to Visual Studio Professional Edition. Visual Studio Community is intended to replace Visual Studio Express, which is also free of charge. As of March 2016, the current version of Visual Studio Express 2015 is available yet. SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 23

24 Resources 7 Resources The installation program for the source code of the GTSL-.NET wrapper classes can be downloaded from the Rohde & Schwarz homepage: A compressed file containing the GTSL installation DVD can be downloaded after registering with Rohde & Schwarz GLORIS: See For more information about the R&S CompactTSVP and R&S PowerTSVP production test platforms and about the associated R&S GTSL software package, go to: SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 24

25 PAD-T-M: /02.05/EN/ Resources Rohde & Schwarz The Rohde & Schwarz electronics group offers innovative solutions in the following business fields: test and measurement, broadcast and media, secure communications, cybersecurity, radiomonitoring and radiolocation. Founded more than 80 years ago, this independent company has an extensive sales and service network and is present in more than 70 countries. The electronics group is among the world market leaders in its established business fields. The company is headquartered in Munich, Germany. It also has regional headquarters in Singapore and Columbia, Maryland, USA, to manage its operations in these regions. Regional contact Europe, Africa, Middle East North America TEST RSA ( ) customer.support@rsa.rohde-schwarz.com Latin America customersupport.la@rohde-schwarz.com Asia Pacific customersupport.asia@rohde-schwarz.com China customersupport.china@rohde-schwarz.com Sustainable product design ı ı ı Environmental compatibility and eco-footprint Energy efficiency and low emissions Longevity and optimized total cost of ownership This Choose an item. and the supplied programs may only be used subject to the conditions of use set forth in the download area of the Rohde & Schwarz website. R&S is a registered trademark of Rohde & Schwarz GmbH & Co. KG; Trade names are trademarks of the owners. Rohde & Schwarz GmbH & Co. KG Mühldorfstraße Munich, Germany Phone Fax SE001_0e Rohde & Schwarz.NET programming interface for R&S GTSL and R&S EGTSL 25

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